What is the date code on your vortec heads. It's stamped on the exhaust side flange, on a machined surface area.
I don't have any pics of my ported vortec heads. I did them quit a while ago. They are on my 406.
2.02x1.60. I never took any pics of those.
With the stock 1.94" valve intake port you are best to just smooth and generally clean up, whats there.
The form under the valve is quite good. At least on the early Canadian made heads. 1996-2000.

The later mexico heads are smaller, low less in stock form and can use dome more work.
How you port thee heads is dependant on how they are going to be used.
The port shape you want for a big cam big valve lft "race" is different than the port and bowl shape thats best when the valve stays relativily close to the seat. small moderate duration and lift.

The vortec head has really good low lift flow in stock form. for a mild mtor do no remove the critcal funnel shape of the bowl under the valve job.
You can generally streamline the guide boss so air can go around it.
Flowing the garden hose thru the port will help you see the natural flow path on a SBC head.

Post all the stamped numbers that are stamped on your heads. May need a light and some emery paper to see them.
On the exhaust flange.

I'll get those numbers today. I did buy a pair of "062" that came off a running 2000 Chevy truck for $125.00 the other day but these i'm playin with are not them. By looking at what i've done on the exhaust in the pictures do you think I have improved them? By lookin at em and imagining(sp) in my mind the air flowing thru them I feel i've helped them but I would like your opinion. I will post the numbers a little later.

I'll get those numbers today. I did buy a pair of "062" that came off a running 2000 Chevy truck for $125.00 the other day but these i'm playin with are not them. By looking at what i've done on the exhaust in the pictures do you think I have improved them? By lookin at em and imagining(sp) in my mind the air flowing thru them I feel i've helped them but I would like your opinion. I will post the numbers a little later.

They are not all the same but an improvement. They should flow well with a little more tweaking. Final cuts are slow and steady. If your tired same them for the next day.

Intakes are probably good for what they are. I would take off the ruff casting maybe even just use sand paper rolls for the intake side. The guide on the intake side are pretty tall. They could be cut but they will probably only be worth a few ponies and could result in bad flow if not done correctly.

Are these your heads your going to run or a set you are using to learn on. If its for learning purposes or all out racing. You can cut the guiide all the way put and leave a flush surface. I would think this should flow the best since these are not swirl port heads and rely on the combustion chamber to turn the air inside the combustion chamber and allow for the final mixing of the air as it flows past the valve and swirls into the port. But this type of short valve guide will crap out the seals and get wobbly real quick unless real guides are put in place first. But it will last 20k miles or a race season. I also thin the valve stems on the lathe to allow for more flow. Just dont do this with sodium filled valves. And back cut the seat area of the valve right down to the seat and allow for better flow over the valve. For bike race engines i will even round the seats with the flapper leaving the valve flat and rpunding the seat in the head and lap the valves in to seat them. Give a lot better flow at low lift levels that will allow the engine to get more air moving sooner in the intake cycle.

Valve size is also usally only at the seat where is touches the head. So moving the seat right out to the edge of valve will increase the effective valve size. And allow more flow at first opening event which allows more air to flow across the entire intake cycle.

Sorry for the short discription it would take hours to go over everything but for your heads a basic clean up should be all that is needed.

First off, Thank you for the great info. I ordered some longer mandrels, for the cartridge rolls, and they should be here today. I didn't get tired I just didn't want to take to much off the guides for fear of exactly what you said, weakening the guide. These are the heads I plan to run and I want them to last alot more than 20K miles. After looking at the pictures on the computer I did see where they are definately not the same. They look different just by lookin at them. I'm gonna get some numbers for FBird in a little bit and post them and i'll do a little "Tweaking" and try to get them as close to the same as possible. I don't have a way of cuttin the valves myself, although I have done it a few times on a schools machine, but I am gonna lap them in good. I "may" talk to my machine shop friend about what you suggested on cuttin the valves. There is a pretty big ridge under the intake seat, do I smooth it out and blend? I've read not to disturb it and also to smooth it out, lol.

Quote:

Originally Posted by hcompton

They are not all the same but an improvement. They should flow well with a little more tweaking. Final cuts are slow and steady. If your tired same them for the next day.

Intakes are probably good for what they are. I would take off the ruff casting maybe even just use sand paper rolls for the intake side. The guide on the intake side are pretty tall. They could be cut but they will probably only be worth a few ponies and could result in bad flow if not done correctly.

Are these your heads your going to run or a set you are using to learn on. If its for learning purposes or all out racing. You can cut the guiide all the way put and leave a flush surface. I would think this should flow the best since these are not swirl port heads and rely on the combustion chamber to turn the air inside the combustion chamber and allow for the final mixing of the air as it flows past the valve and swirls into the port. But this type of short valve guide will crap out the seals and get wobbly real quick unless real guides are put in place first. But it will last 20k miles or a race season. I also thin the valve stems on the lathe to allow for more flow. Just dont do this with sodium filled valves. And back cut the seat area of the valve right down to the seat and allow for better flow over the valve. For bike race engines i will even round the seats with the flapper leaving the valve flat and rpunding the seat in the head and lap the valves in to seat them. Give a lot better flow at low lift levels that will allow the engine to get more air moving sooner in the intake cycle.

Valve size is also usally only at the seat where is touches the head. So moving the seat right out to the edge of valve will increase the effective valve size. And allow more flow at first opening event which allows more air to flow across the entire intake cycle.

Sorry for the short discription it would take hours to go over everything but for your heads a basic clean up should be all that is needed.

What is the date code on your vortec heads. It's stamped on the exhaust side flange, on a machined surface area.
I don't have any pics of my ported vortec heads. I did them quit a while ago. They are on my 406.
2.02x1.60. I never took any pics of those.
With the stock 1.94" valve intake port you are best to just smooth and generally clean up, whats there.
The form under the valve is quite good. At least on the early Canadian made heads. 1996-2000.

The later mexico heads are smaller, low less in stock form and can use dome more work.
How you port thee heads is dependant on how they are going to be used.
The port shape you want for a big cam big valve lft "race" is different than the port and bowl shape thats best when the valve stays relativily close to the seat. small moderate duration and lift.

The vortec head has really good low lift flow in stock form. for a mild mtor do no remove the critcal funnel shape of the bowl under the valve job.
You can generally streamline the guide boss so air can go around it.
Flowing the garden hose thru the port will help you see the natural flow path on a SBC head.

Post all the stamped numbers that are stamped on your heads. May need a light and some emery paper to see them.
On the exhaust flange.

The numbers I found are: 10, 062, 8, 18, M127, GM-D, 12558062. Are these what you need?

all this porting is a great idea.Remember that almost all the heads need the most work on the exhaust side. Doesnt matter how much air goes in the intake side if it cannot leave

This is 100 percent true. Most factory heads work well because the intake side is under a lot pess pressure to pull the charge in than the exhuast side. The exhuast is going to come out. Because the piston is going to force it out. Most factory heads are very unbalaced because of this fact.

But with heads designed for efi you got to assume it is also built to run with little to no over lap. Now with a poor flowing exhuast port a larger cam with good overlap will not scavange like it is designed to so the exhuast ports always need attention first when starting with an efi head.

Most ford guys are amazed to see the exhuast bump in the 80s and 90s 5.0 engines. It blocks most of the port and by itself its worth 20 hp and will make sure any bolt on you install only works so well. This is also the reason some cars will respond to bolt ons and make 500hp and other will never pass the 300 mark.

On the intake side in this case i would think there isnt much power to be gained past the removing of the ruff casting surface to a smoother sanded surface.

Some none efi heads have the opposite problems. Balance is the key and getting the ports to flow enough to support the rpm the cam is requesting from the engine.

This is 100 percent true. Most factory heads work well because the intake side is under a lot pess pressure to pull the charge in than the exhuast side. The exhuast is going to come out. Because the piston is going to force it out. Most factory heads are very unbalaced because of this fact.

But with heads designed for efi you got to assume it is also built to run with little to no over lap. Now with a poor flowing exhuast port a larger cam with good overlap will not scavange like it is designed to so the exhuast ports always need attention first when starting with an efi head.

Most ford guys are amazed to see the exhuast bump in the 80s and 90s 5.0 engines. It blocks most of the port and by itself its worth 20 hp and will make sure any bolt on you install only works so well. This is also the reason some cars will respond to bolt ons and make 500hp and other will never pass the 300 mark.

On the intake side in this case i would think there isnt much power to be gained past the removing of the ruff casting surface to a smoother sanded surface.

Some none efi heads have the opposite problems. Balance is the key and getting the ports to flow enough to support the rpm the cam is requesting from the engine.

Just some general info to spur discussion.

it's actually 100% wrong... a 5cfm gain on the intake is worth more than a 5cfm gain on the exhaust, even though the % difference is smaller.

Also, the Vortec intake tract is better than previous sbc heads, but the exhaust is NOT worse, its actaully a hair better too, just not as much as the intake. People get caught up in the intake/exhaust ratio and fail to see what they're really looking at on the exhaust side. Also, there's NO crossover, which is a pretty big deal compared to most other stock sbc heads.

A really good example is porting on F E heads. want to wake up a 390,port the exhaust uncork the exhaust system.Old dodge sb...port exhaust side.
want to make power with vortec heads,open the exhaust.
best after market heads have a high exhaust ratio.
dont want to use a split duration cam or thumper cam,port the exhaust
how many high powered cars have small exhaust?

it's actually 100% wrong... a 5cfm gain on the intake is worth more than a 5cfm gain on the exhaust, even though the % difference is smaller.

Also, the Vortec intake tract is better than previous sbc heads, but the exhaust is NOT worse, its actaully a hair better too, just not as much as the intake. People get caught up in the intake/exhaust ratio and fail to see what they're really looking at on the exhaust side. Also, there's NO crossover, which is a pretty big deal compared to most other stock sbc heads.

Can you please explain why you think vinnie is wrong since i know he is right and explained it clearly. Can you do the same for your side.

How does this 5cfm reference actually make a difference in the disscussion. Its just jibberish. It doesnt even relate to the real world since the ports cfm rating come from a flow bench that does not scavenge the exhuast or flow at the speed that is even close to the actual exhuast speed at redline. Flow benches push air thru the ports around 25-50 mph the exhuast will come out of the exhust port well past 300 mph.

If the ratio is not correct the engine will not be effecient the VE will drop and will never hit its true power potential.

During overlap the exhuast scavaging will actually pull the a/f mix from the intake port while both valves are open and even let it run out the exhuast port then the pressure wave kicks back at the collector and pushes the a/f mix back into the cylinder and possibly over 100 percent ve with proper cam and tuning.

A really good example is porting on F E heads. want to wake up a 390,port the exhaust uncork the exhaust system.Old dodge sb...port exhaust side.
want to make power with vortec heads,open the exhaust.
best after market heads have a high exhaust ratio.
dont want to use a split duration cam or thumper cam,port the exhaust
how many high powered cars have small exhaust?

porting the exhaust does help, so you'd be a fool not to do it if you're searching for max power, but it doesn't help as much as the intake.

You're making sweeping presumptions that really have no basis. And there's not a damn thing wrong with a split pattern cam or even a reverse split pattern cam- the cam should match the application and that means almost NEVER using the same lobes on the intake and exhaust.

If you have to pick a side to spend your time on spend it on the intake. And a very well ported set of Vortecs with a stock valve will pick up 30-40cfm on the intake at about .550" lift. Properly built that can mean about 60hp.

And I am NOT saying porting the exhaust won't help too, if you can they should both be done. It is just not as significant as the intake.

WOW, I really appreciate everyones input and opinions. I got the exhaust ports done where they all match, to my eyes anyway, lol. I just came in to eat and am going back out to pull the studs and tap the bosses. I have a doctors app. Monday but plan on starting on the intake porting when I get home but, I have a question. I bought these studs, Mr. Gasket Screw-In Rocker Arm Studs 1076 - SummitRacing.com. How do I go about torqueing them? I plan on using Loctite on the threads and the only thing I can think of is to triple lock nut them and torque them that way. What do ya'll think?

WOW, I really appreciate everyones input and opinions. I got the exhaust ports done where they all match, to my eyes anyway, lol. I just came in to eat and am going back out to pull the studs and tap the bosses. I have a doctors app. Monday but plan on starting on the intake porting when I get home but, I have a question. I bought these studs, Mr. Gasket Screw-In Rocker Arm Studs 1076 - SummitRacing.com. How do I go about torqueing them? I plan on using Loctite on the threads and the only thing I can think of is to triple lock nut them and torque them that way. What do ya'll think?

Not sure about that one. You can use two nuts tighten together but not great for tq specs.

Also if you lock tight them down they may be hard to remove. For guide plates later on.

I agree lock tight is a good idea. Just maybe not red unless they call for red locktight. Be sure its high temp. That part of the head gets very hot.

I got to recommend studs with the nuts on them. But i know you have what you have and dont want to send them back. Just feel like i should say it.

Leave the stock studs alone. They do not pull out like the stock studs on the old heads do.
They are fine as is for most hi perf street applcations. even with high perf springs.
Just use a self guided style rocker arm ( stock or aftermarket)

The risk of breaking the the stud boss by trying to pull them out exceeds the
preceived benefit of a screw in stud.
Again, these stock pressed in studs do not cause the issues that the old heads did.

LEAVE THE STUDS ALONE
What cam and rockers are you using. You are probabily getting all carried away for a bunch of nothing.

Man, I sure am glad I got a phone call and didn't make it back out to the garage and you caught me before I started. Thanks FBird. I hadn't read, seen anywhere or heard anything about the studs on Vortecs and just assumed they were like any other sbc head. I was going to put screw studs in just in case I ever wanted to go with a bigger cam one day. I'm running the Summit K1103, 272/282-.442/.465 on a 112 lsa and running the stock rockers that came with these heads unless I change my mind and then i'll run these COMP Cams Magnum Steel Roller Tip Rocker Arms 1417-16 - SummitRacing.com.

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